Self-erecting crane



Feb. 5, 1946. R. G. L .E TOURNEAU I SELF-ERECTING CRANE Filed Dec. 9, 1944 3 Sheets-Sheet 1 INVENTOR R. G. Le Tourn eaw BY zAt ATTORNEYS 1946. R. 6. LE TOURINEAU 2,394,314

SELF-ERECTING 01mm Flled Dec 9, 1944 s Sheets-Sheet 2 INVENTOR GIeZbumeau BY Mr: M

- ATTORNEYS Feb. 5,1946. R. 6. LE TOURNEAU SELF-ERECTING CRANE 3 Sheets-Sheet 5 Filed Dec. 9, 1944 R. G. LeTurJ-Jeau,

Patented Feb. 5, 1946 SELF-ERECTING CRANE Robert G. Le Tourneau, Peoria, 111., assignor to R. G. Le Tourneau, Inc., Stockton, Caiif., a

corporation of California Application December 9, 1944, Serial No. 567,342

7 Claims.

This invention relates in general to a portable or mobile crane of self-propelled type, and in particular the invention is directed to, and it is an object to provide, a folding crane assembly which is self-erecting from a lowered or folded position.

Another object of the invention is to provide,

in a portable crane, a foldable self-erecting crane assembly as above, and a power actuated cable system operative to cause folding of the crane assembly from an upstanding position and to control erection of said crane assembly from folded position; there being a manually releasable latch unit, arranged to lock the crane assembly in folded position.

A further object of the invention is to provide a portable crane comprising a tractor, a rearwheel truck, a tubular draft body connecting the tractor and rear wheel truck, and a crane assembly pivoted adjacent but short of its lower end on the truck for forward and downward folding movement; there being a spring unit anchored to and included in part in said tubular draft body and connected to the crane assembly below its pivot whereby to urge said assembly to an erected position from folded position, and means to control erection of the crane assembly.

An additional object is to provide a crane as in the preceding paragraph in which said spring unit includes a helical spring in the tubular draft body, and a cable connected between said spring and the crane assembly below its pivot; there being means on the crane assembly operative to maintain straight-line pull on the cable when said crane assembly is swung from upstanding to foldedposition.

A further object of the invention is to provide a simple and inexpensive, device, and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several said assembly.

Figure 4 is a cross section on line 44 of Fig. 3, illustrating the cross-sectional configuration of the cable guide quadrant.

Referring now more particularly to the characters of reference on the drawings the numeral I indicates generally in outline a tractor, preferably of the two-wheel Tournapull type; such tractor including at the rear end thereof a tractor engine actuated, multiple-drum power control unit ,2.

At the rear end the crane includes a wheel truck, indicated generally at 3, and which truck includes a fixed cross beam I having depending end brackets 5 which carry spindles 6 on which the rear wheels I are journaled.

The tractor l and rear wheel truck 3 are connected together by a longitudinally extending tubular draft beam 8 which is disposed at a forward and upward incline from said truck 3; the rear and lower end portion of the draft beam 8 being connected with a frame portion 9 of said truck in a manner so that the lower end of said beam 8 is disposed ahead of the axis of spindles 6 and with the extended axial center line of said beam projecting below said spindle axis.

At its forward and upper end the draft beam 8 is connected to the tractor l by a draft coupling III which permits ofsteering of the tractor relative to the remainder of the implement.

The foldable crane assembly comprises a mast or frame unit ll pivotally mounted adjacent but short of its lower end, as at l2, to the cross beam 4 of the rear wheel truck 3, rearwardly of the spindles 6, for downward and forward folding movement from an erected position, as in Fig. 1, to a lowered position, as in Fig. 2, and in which lowered position the frame unit H is substantially parallel to the draft :beam 8. The mast or frame unit ll includes within the same a vertically movable elevator carriage l3 guided in said frame unit for cable-controlled raising and lowering movement. The cable, which is operative to effect such movement, is indicated at H, and within the frame unit ll passes about a sheave IS in the latter andthence' extends forwardly over a fairlead sheave l6 suspending from the draft coupling in, and thence depends to connection with one of the drums of the power control unit 2. Aboom I! projects in fixed relation outwardly from the elevator carriage l3, and when the frame unit II is erected said boom is disposed at an upward and rearward incline. At its outer end the boom 11 includes a lift hook. as shown.

If it is desired that the crane include a cable 11a system a cable, indicated in broken lines at i 8, runs from another drumpf the power control unit 2 forwardly over a direction chan ing sheave I 9 on the frame unit ii adjacent its lower end, thence extends upwardly over a sheave 2:; fixed in the upper portion of the frame unit i l, and finally extends forwardly over a sheave 2| on the outer end of the boom l1, and from which sheave 2| the cable 18 depends in load lifting relation.

The particular structural arrangement of the elevator carriage i3, and the cable means for operating the same form no part of the present invention, which invention is directed particularly to the means for raising and lowering the crane assembly of frame unit I i and boom l1, and which means comprises the following:

A heavy-duty helical compression spring 22 of substantial length is disposed within the tubular draft beam 8 and seats at its lower end against a head 23 in the corresponding end of said beam 8. A cable 24 is anchored at its lower end, as at 25, to the frame unit H centrally of the sides of the latter and at a point some distance below the pivot l2. From the anchor 25 the cable extends through an opening 26 in head 23, and thence passes centrally .through the spr-irm 22 and is attached to a head 21 which rides against the upper end of the spring 22. The anchor 25 is attached to the frame unit ii at such point that when the frame unit is in erected position the cable 24 extends axially through the spring 22 and draft beam 8. As it is desirable that such position of the cable 24 be maintained when the frame unit H is in lowered position, in order that the cable may exert a straight-line pull at all times, the following arrangement is provided:

A cable guide quadrant 28 is fixed on the frame unit ll adjacent the bottom thereof and in forwardly projecting relation in the vertical plane of the cable 24; said quadrant encircling the cross beam 4 and being disposed concentric to the pivotal axis 1 2 of frame unit II. The quadrant 28 is thus disposed in all positions of the frame unit H substantially tangent to the projected or' The crane assembly of frame unit i l and boom I1 is power folded from erected position by means of the following arrangement:

A cable 29 is reeved between fixed sheave blocks 30 and 3| on the upper end of the frame unit and on the draft beam 8 adjacent its forward end, respectively. The cable 29 includes a pull lead 32 which extends forwardly over a fairlead sheave 33 and thence runs downwardly to a corresponding drum of the power control unit 2.

The crane assembly of frame unit H and boom I1 is releasably held in folded or lowered position independently of the cable 29 by means of a spring pressed latch unit 34 mounted in connection with the support for sheave 3| and cooperating with a latch plate 35 mounted on the support for sheave 30. A spring returned pull rod 36 extends forwardly to a termination as a handle 31 adjacent the operators seat 38 of the tractor I.

When it is desired to swing the crane assembly from an erected position to a folded position, the operator actuates the power control unit 2 so as to pull in on cable lead 32, which shortens the block and tackle formed by cable 29. With shortening of such block and tackle the crane assembly swings forwardly and downwardlyuntil the latch unit enga' 'es with latch plate 35. Thereafter, it

is not necessary to maintain a power control unit tension on cable lead 32. When the crane assembly is thus folded the spring 22 is compressed and loaded.

To erect the crane assemblythe latch unit 34 is released and the cable lead 32 paid out from the power control unit, which permits said crane assembly to erect under the influence of expansion of spring 22. The desired working position relative to vertical of the crane assembly is controlled by the length of the block and tackle unit formed by the cable 29. As is evident, the frame unit ll may be swung rearwardly relative to vertical in order to increase the reach of the as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure --from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent is desired:

1. A portable crane comprising a wheel supported body including a longitudinally extending tubular draft beam, a crane assembly pivoted on the body above and to the rear of said beam for forward and downward folding movement, a loaded spring disposed in the beam and anchored at one end thereto, a cable connected between the other end of the spring and to the crane assembly below the pivot of the latter, whereby the spring tends to erect said crane assembly, means to fold the crane assembly and control its erection, a cable guide quadrant mounted on the crane assembly concentric to the pivotal axis of the crane assembly, said cable engaging said quadrant whereby to guide the cable and maintain a straight line pull on the cable in all positions of the crane assembly.

2. A combination as in claim 1, in which the tubular beam is disposed at an upward and forward incline from its rear end, the longitudinal axis of the beam being substantially tangent to the cable guide quadrant.

3. A portable crane comprising a tractor and a wheel mounted truck, a tubular draft member extending forwardly and upwardly from the truck to apivotal connection with the tractor and forming the sole connection between said tractor and truck, a crane assembly pivotally mounted on the truck at a point above and to the rear of said draft member for forward and downward folding movement into substantial parallelism with said member, a loaded spring disposed in said draft member and anchored at one end thereto, a cable connected between the other end of the spring and to the crane assembly below the pivot point of the latter,- whereby the spring ascents tends to erect said crane assembly, a cable connection between the outer ends of the draft member and crane assembly, respectively, said cable being operable to pull the assembly into such folded position, and means on the tractor for so operating such cable means.

4. A portable crane comprising a tractor and -a wheel mounted truck, the truck comprising a cross beam, depending brackets at the ends of the beam, wheels journaled in the brackets, a tubular draft beam pivotally mounted on the tractor and extending rearwardly and downwardly to a connection centrally of said cross beam, the extended axial center line of the draft beam projecting below the axis of the rear truck wheels, a crane assembly pivoted on the cross beam above and to the rear of the lower end of the draft beam and adapted to fold forwardly and downwardly, a loaded spring dispose in said draft beam and anchored at one end thereto, a cable connected to the other end of the spring and to v the crane assembly below the pivot of the latter, whereby the spring tends to erect the crane assembly, and means to fold the crane assembly and to control its erection under the influence of the spring.

5. A combination as in claim 4 and includin therewith a. guide quadrant on the lower end of the crane assembly and which quadrant encircles the wheel axes and the pivot axis of the craneassembly and isconcentric with the latter,

the spring cable engaging the quadrant whereby to guide the cable and maintain a straight line pull onv the cable in all positions of the crane assembly.

6. A portable crane comprising a tractor and a wheel mounted truck, a draft beam connecting the tractor and truck, a crane assembly pivoted on the truck for forward and downward folding movement into substantial parallelism with said beam, means to efiect such folding movement,

means to erect the crane assembly, a latch means interposed between the beamand crane assembly which automatically latches when the crane assembly is'moved to folded position, and manual means to release the latch when the crane assembly is to be moved to erect position.

7. A portable crane comprising a tractor and a wheel mounted truck, a draft beam connecting the tractor and truck, a crane assembly pivoted on the truck for forward and downward folding movement into substantial parallelism with said beam, means to effect such folding movement, means to erect the crane assembly, a latch plate depending from the crane assembly, a spring pressed latch mounted on the beam and operable to automatically engage the latch plate when the crane assembly is moved to folded position, and a spring return pull rod on the latch operable to release the latch from the plate when the crane assembly is to be moved to erect position.

7 ROBERT G. LE 'IOURNEAU.- 

